(1) Field of the Invention
This invention relates to governors and more particularly to pneumatic speed regulators for variable speed engines.
(2) Description of the Prior Art
Adjustable flyweight governors for regulating the speed of large internal combustion engines or turbines are well known and have reached a high stage of development. A typical example of such would be a governor as manufactured for many years by Woodward Governor Company of Ft. Collins, Colorado. Basically, these governors rotate the flyweight from a drive shaft which is driven from the engine. (As used herein the term "engine" is meant to also include a variable speed turbine.) The position of a speeder plug against a speeder spring which bears against a thrust bearing on the toe of the flyweight will determine the speed of the engine. In operation, the thrust bearing will normally have a fixed position. Upward movement of the thrust bearing will indicate the speed of the engine is too fast and this upward movement will be translated to a valve which, through a hydraulic system, will decrease the fuel to the engine. A speed above the set speed will result in an opposite reaction.
The governors also have many additional adjustments and refinements not important here.
Therefore, the speed of the engine is actually controlled by the position of the speeder plug.
In many installations, satisfactory operation is obtained by manually setting the speeder plug for the desired speed.
However, in certain installations it is desired to automatically set the speed in the engine. E.g., in the operation of a compressor station, it is desirable to have the compressor and, thus, the engine operate at a speed responsive to the pressure of the incoming gas. I.e., the lower the gas pressure coming into this station, the slower the speed of the engine.
Before my invention, workers in the art would make the speed responsive to the external conditions (e.g., the pressure of the incoming gas at a pressure station) by attaching a pneumatic actuator externally of the governor by attaching the output of a pneumatic diaphragm to the arm on the speed adjustment shaft, which was linked to the speeder plug.